Many electronic systems provide the capability to supplement the functionality of the system by providing an interface through which additional electronic circuitry can be added to the system. For example, with reference to FIG. 1, a typical computer system 10 provides several connector slots 11 which are adapted to accept add-in cards 12. The add-in cards 12 may be retained by the mechanical forces between the connector 11 on the system board 13 and the card edge connector 14 on the add-in card 12. In many cases a bracket 15 is provided on the add-in card 12 which is secured to the chassis of the system at one end with a screw.
Some memory devices, which are relatively small, include latches on both ends of the memory connector. The latches help retain the memory card in the slot and may also be used to eject the memory card.
The power consumption and complexity of computer add-in cards has been increasing due to performance demands. For example, conventional high performance video cards may require power of about 25 watts and may weigh about 400 grams. As the required power increases, the weight of the add-in card consequently increases due to the need for more complex thermal solutions including larger heat sinks and fans. Even without increased power demands, the mass of the add-in card may increase due to larger card size and more devices and/or components on the add-in card.
If an add-in card is not sufficiently retained, the card can be displaced, or even dislodged from the system board connector, e.g. due to shock and vibration. This can result in an open circuit or even structural damage. The severity of the problem mainly depends on the card mass, the location of the center of gravity, and the card/connector design. Add-in cards with a large relative mass also have more inertia during shock and/or vibration events. The increased card inertia applies a larger impact force on constraining parts of the card such as the card connector. This can potentially cause failures such as the connector housing pulling off from soldered pins and/or other damage on the connector housing itself.